-more-resistant endospores of thermophilic bacteria may survive but they will not germinate and grow under normal storage conditions

Define Disinfection

Destruction of vegetative (growing) pathogens

-may make use of physical or chemical methods

Define Antisepsis

Destruction of vegetative pathogens on living tissue

-treatment is almost always by chemical antimicrobials

Define Degerming

removal of microbes from a limited area, such as the skin around an injection site

-mostly a mechanical removal by an alcohol-soaked swab

Define Santization

treatment is intended to lower microbial counts on eating and drinking utensils to safe public health levels

-may be done with high-temperatue washing or by dipping into a chemical disinfectant

What does it mean when something is "cidal" or "static"?

cidal- kills whatever it is made for ex. mesocidal

static-halts growth (like a fridge is microbial static for mesophiles)

What is DRT? What are the two factors that can affect DRT?

DRT is the time it takes to kill 90% of the microbial population

-varies between MOs

*the Harsher the procedure, the shorter the DRT

*the easier the MO to kill, the shorter the DRT

*does not vary under a defined set of conditions (constantly killing 90%)

How can the number of microbes and degree of microbial resistance influence the effectiveness of microbial treatments?

More microbes= more time to kill them all

The easier they are to kill, the less time it takes to kill them

How can environmental influences and exposure time influence the effectiveness of microbial treatments?

Cold, dirty objects are harder to treat-disinfection is a chemical process, which occurs faster at warmer temperatures-dirt:organic matter; can absorb disinfectant and prevent the killing of MO*the longer you kill, the more you kill

What are the three factors of cell anatomy that are important in how microbial control agents effect the cells?

These 3 are targets for killing

membrane-regulates what enters the cell. If damaged, cell with lyse

proteins-do certain jobs that keep the cell alive. If damaged, cell will die

nucleic acids-controls the synthesis of proteins. If damaged cell will die

What is the purpose of boiling? What are it's uses and limitations?

Common uses: for cleaning drinking water, boil for 2 minutes

*boiling is 100C

how? It denatures the proteins of the MO (like a hardboiled egg)

Limitations: some spores survive boiling

*form of disinfecting or sanitization

What is the purpose of an autoclave? How does it work? What are it's uses and limitations?

Works like a pressure cooker

-the steam is much hotter than boiling

-121C for 15 minutes

Microbes cannot survive

-reliable sterilization

limitation: only for objects that can get hot and wet

What is the purpose of pasteurization? How does it work? What are it's uses and limitations?

Pasteur's Idea-goal is to kill pathogens and lower total MO count without significantly altering taste or nutrient content

uses: milk, beer, fruit juice, canned crab meat, marschino cherries

timing: 63C/30min;72C/15sec;

UHT 74C-->140C-->70C in 5 seconds

UHT: ultra high temperature

-it extends the products shelf life and makes the product safe to consume

What is the purpose of oven sterilization? How does it work? What are it's uses and limitations?

Uses Dry Heat

-170C for 2 hrs

Organic Molecules + Heat--> CO2 + H2O

Air conducts heat much more porrly than water, that's why it takes longer than autoclaving

limitations: use for objects that can get hot but not wet (like glassware)

related methods: flaming loops, incineration of infectious waste

What is the purpose of filtration? How does it work? What are it's uses and limitations?

This is used for fluids that are heat-liable, or damaged by heat such as culture media enzymes, vaccines, and antibiotic solutions

Uses: can be used for water at (.2μm)

HEPA filters (.3μm) for burn wards, clean rooms, operating filters

What is the purpose of refrigeration? How does it work? What are it's uses and limitations?

A mold inhibitor, often found in soft drinks, cheeses and baked goods (like snack cakes)

Sodium Benzoate

same as potassium sorbate

Glutaraldehyde

highly effective; one of the few chemicals considered to be a sterilent (when properly used); bind to and denature cell proteins; the active agent in our laboratory bench top cleaning solutions (wavicide)